Image forming apparatus with an air supplying unit having an air opening provided in a receiving unit

ABSTRACT

An image forming apparatus of the present invention comprises an apparatus body having a document table portion on which a document is placed, a scanning unit provided inside the apparatus body to optically scan an image of the document placed on the document table portion, an image forming unit for forming a developer image on a photosensitive drum in accordance with the image information scanned by the scanning unit, a transfer charger for transferring the developer image formed by the image forming unit on a sheet, a fixing unit for fixing the developer image transferred by the transfer charger on the sheet, an ejecting roller for ejecting the sheet on which the developer image is fixed by the fixing unit to the outside, a sheet receiving unit provided below the scanning unit inside the apparatus body to receive the sheet ejected from the ejecting roller, and a blowing unit for blowing cool air to the sheet receiving unit along a lower surface part of the scanning unit.

The present application is a continuation of Ser. No. 11/292,107, filedDec. 2, 2005, which is a continuation of Ser. No. 11/054,548, filed Feb.10, 2005, which is a continuation of Ser. No. 10/888,006, filed Jul. 12,2004, which is a continuation of Ser. No. 10/434,274, filed May 9, 2003,now U.S. Pat. No. 6,771,917, which is a continuation of Ser. No.10/198,132, filed Jul. 19, 2002, now U.S. Pat. No. 6,611,667, which is acontinuation of U.S. application Ser. No. 09/738,323, filed Dec. 18,2000, now U.S. Pat. No. 6,438,339, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an image forming apparatus for use as,for example, an electrophotographic copier, for ejecting a sheet onwhich an image is transferred to a sheet receiving unit of an apparatusbody.

An image forming apparatus such as an electrophotographic copiercomprises a document table glass on which a document is to be placed, onan upper part of the apparatus body. An image scanner for opticallyscanning an image of the document is provided under the document tableglass. The image information scanned by the image scanner is formed asan electrostatic latent image on a photosensitive drum. A developer issupplied to the electrostatic latent image by a developing unit and,therefore, the electrostatic latent image becomes a developer image. Thedeveloper image is transferred to a sheet, which is regarded as animage-transferred material. The sheet on which the developer image istransferred is conveyed by a conveyance mechanism. The transferred imageis fixed on the sheet by a fixing unit during the conveyance and thenthe sheet is ejected.

Incidentally, the sheet is ejected to the outside of the apparatus bodyto simplify the structure of the apparatus body or to convey the sheetlinearly.

On the other hand, recently, the apparatus allowing the sheet to beejected to the sheet receiving unit provided inside the apparatus bodywhile making the printed surface of the sheet face downward has beendeveloped in order to maintain the secrecy of a document image printedon the sheet, to make the distance of conveyance of the sheet shorter,and to save the space. The sheet ejected to the sheet receiving unit isheated at the fixing unit before the ejection. The sheet therefore emitsthe heat inside the sheet receiving unit.

However, the image scanner is positioned at the uppermost part of theapparatus body when the function thereof is considered, and the sheetreceiving unit is arranged immediately under the image scanner. Thus,the temperature of the image scanner is raised by the heat emitted fromthe sheets collected in the sheet receiving unit. As the image scannercomprises the optical components and the electronic components, the riseof the temperature causes a problem that a bad influence may be given tothe performances of the optical components and the electronic componentsand thereby the image may be deteriorated.

To prevent the rise of the temperature of the image scanner, suction ofoutside air by use of a fan or the like to cool the image scanner isconceived.

However, the image scanner contains the optical components and is easilyaffected by dust and the like. For this reason, it is desirable not toprovide an opening portion such as an air inlet on the image scanner,and it is not preferable to cool the image scanner by sucking theoutside air into the image scanner.

BRIEF SUMMARY OF THE INVENTION

The present invention is accomplished in consideration of theabove-described circumstances. The present invention aims to provide animage forming apparatus capable of preventing the rise of thetemperature of the image scanner caused by the heat of theimage-transferred members ejected to the sheet receiving unit, withoutsucking the outside air into the image scanner.

An image forming apparatus according to the present invention comprisesan apparatus body having a document table portion on which a document isplaced, scanning means provided inside the apparatus body, for opticallyscanning an image of the document placed on the document table portion,image forming means for forming a developer image on an image carrier inaccordance with image information scanned by the scanning means,transfer means for transferring the developer image formed by the imageforming means on an image-transferred member, an ejecting unit forejecting the image-transferred member on which the developer image istransferred by the transfer means to the outside, a sheet receiving unitprovided inside the apparatus body, for receiving the image-transferredmember ejected from the ejecting unit, and blowing means for blowingcooling air to the sheet receiving unit.

Further, an image forming apparatus of the present invention comprisesan apparatus body having a document table portion on which a document isplaced, scanning means provided inside the apparatus body, for opticallyscanning an image of the document placed on the document table portion,image forming means for forming a developer image on an image carrier inaccordance with image information scanned by the scanning means,transfer means for transferring the developer image formed by the imageforming means on an image-transferred member, an ejecting unit forejecting the image-transferred member on which the developer image istransferred by the transfer means to the outside, a sheet receiving unitprovided at a lower part of the scanning means inside the apparatusbody, for receiving the image-transferred member ejected from theejecting unit, and blowing means for blowing cooling air to the sheetreceiving unit along a lower surface part of the scanning means.

Moreover, an image forming apparatus of the present invention comprisesan apparatus body having a document table portion on which a document isplaced, scanning means provided inside the apparatus body, for opticallyscanning an image of the document placed on the document table portion,latent image forming means for forming an electrostatic latent image onan image carrier in accordance with image information scanned by thescanning means, developing means for supplying a developer to theelectrostatic latent image formed by the electrostatic latent imageforming means to form a developer image, transfer means for transferringthe developer image formed by the developing means on animage-transferred member, fixing means for fixing the developer imagetransferred by the transfer means on the image-transferred member, anejecting unit for ejecting the image-fixed member on which the developerimage is fixed by the fixing means, a sheet receiving unit provided at alower part of the scanning means inside the apparatus body, forreceiving the image-transferred member ejected from the ejecting unit,and blowing means for blowing cooling air to the sheet receiving unitalong a lower surface part of the scanning means.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a view showing an internal structure of an electrophotographiccopier according to an embodiment of the present invention;

FIG. 2 is a view showing a structure of an optical image scanner;

FIG. 3 is a side view showing an air blower provided inside a main bodyof the copier;

FIG. 4 is a front view showing an air outlet of the air blower; and

FIG. 5 is a perspective view showing the air outlet of the air blower.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention will be explained below withreference to the drawings.

FIG. 1 is a view showing a structure of an electrophotographic copieraccording to an embodiment of the present invention.

In the figure, reference numeral 1 denotes a main body of an apparatus.A document table 2 on which a document is to be placed is provided on anupper part of the apparatus body 1. An optical image scanner 3 forscanning an image on a document is provided under the document table 2.A sheet-receiving unit 4 for receiving a sheet P as an image-transferredmember, which is ejected to the outside after an image is formed on themember, is provided under the optical image scanner 3. An exposure unit5 for forming an image on a photosensitive drum 7 to be described laterin accordance with the image information is provided under thesheet-receiving unit 4.

An image formation unit 6 serving as image forming means is providedbeside the exposure unit 5. The image formation unit 6 comprises thephotosensitive drum 7, which can be freely rotated in a directionindicated by an arrow. An electrifier 9, a developing unit 10, atransfer charger 11, a cleaning device 12 and a destaticizer 13 areprovided in order around the photosensitive drum 7 in the rotationaldirection of the photosensitive drum 7.

The electrifier 9 uniformly electrifies the surface of thephotosensitive drum 7. The developing unit 10 supplies a developer to anelectrostatic latent image formed on the photosensitive drum 7 anddevelops the image. The transfer charger 11 transfers the developerimage formed on the photosensitive drum 7 on the sheet P. The cleaningdevice 12 removes the developer remaining on the photosensitive drum 7after the transfer of the developer image. The destaticizer 13 removesthe electric potential remaining on the photosensitive drum 7.

A fixing unit 15 for fixing the image on the sheet P is provided abovethe image formation unit 6. A sheet conveyance path 16 in which thesheet P is conveyed is provided between the fixing unit 15 and the imageformation unit 6. An alignment roller 17 for aligning the sheet P fed tothe image formation unit 6 is provided under the sheet conveyance path16. An ejecting roller 18 serving as an ejecting unit for ejecting thesheet P is provided over the sheet conveyance path 16. The sheet Pejected from the ejecting roller 18 is fed into the sheet receiving unit4 while the image-printed surface faces downward to maintain thesecrecy.

On the other hand, paper feed cassettes 19 a to 19 d for containing theSheets of various sizes are provided on a plurality of stages on a lowerpart inside the apparatus body 1. The sheets inside the paper feedcassettes 19 a to 19 d are picked up by the rotation of pickup rollers21. The sheets are separated one by one and fed by separating rollers22.

A vertical conveyance path 23 is provided along the sheet feedingdirection of the paper feed cassettes 19 a to 19 d on the plural stages.Conveying roller pairs 24 are provided in the vertical conveyance path23 while having a predetermined distance therebetween in the verticaldirection. A conveying roller pair 25 for conveying the sheet P towardthe alignment roller 17 is provided on the upper part of the verticalconveyance path 23.

FIG. 2 shows a structure of the image scanner 3.

The image scanner 3 comprises first and second carriages 27 and 28 thatare made to run along the document table 2. A light source 30 and afirst mirror 31 are mounted on the first carriage 27, and second andthird mirrors 33 and 34 are mounted on the second carriage 28. Animage-forming lens 37, a photoelectric conversion device 38 (hereinaftercalled a CCD) for receiving the reflected light and converting the imageinformation into an electric signal, and a driver circuit 39 of the CCD38 are aligned in the path of the light reflected by the third mirror34.

A drive wire 35 is bridged between the first and second carriages 27 and28. Both end parts of the drive wire 35 are fixed at fixing portions 41a and 41 b. A middle part thereof is bridged on fixing pulleys 42 a and42 b, and a driving pulley 36 a of the drive motor.

The drive wire 35 is wound in the normal or opposite direction by thenormal or opposite rotation of the drive pulley 36 a and thereby thefirst and second carriages 27 and 28 are made to run along the documenttable 2 in the normal or opposite direction.

Next, the image forming operation will be explained.

When a copy button (not shown) is pushed down, the first and secondcarriages 27 and 28 start to move from a home position and scanning thedocument is started. Thus, the light emitted from the light source 30 isirradiated to the document placed on the document table 2. The lightreflected from the document is received by the CCD 38 via the first tothird mirrors 31, 33 and 34, and the lens 37. The light image data isconverted by the reception of the light from an analog signal to adigital signal, which is subjected to the correction processing requiredfor images. After that, various kinds of operations (for example,scaling, trimming, and the like) are carried out and the imageinformation signal is transmitted to the exposure unit 5.

On the other hand, at this time, the surface of the photosensitive drum7 is uniformly electrified by the electrifier 9 and scanned by theexposure unit 5 using the laser beam corresponding to the imageinformation, so that the electrostatic latent image is written on thesurface of the photosensitive drum 7. The electrostatic latent image isdeveloped by the developer supplied from the developing unit 10 so as tobe a developer image. The developer image is transferred onto the sheetby the transfer charger 11. The sheet on which the developer image istransferred is peeled off from the photosensitive drum 7 because of theelasticity of the sheet and conveyed to the fixing unit 15. Thedeveloper image on the sheet is heated and fixed thereon by the fixingunit 15. After the fixation, the sheet is ejected and collected from theejecting roller 18 to the sheet receiving unit 4 while theimage-transferred surface faces downward. After the transfer of thedeveloper image, the developer remaining on the photosensitive drum 7 isscraped and removed therefrom by the cleaning unit 12. Then, the surfaceof the photosensitive drum 7 is destaticized by the destaticizing lamp13 and the operation proceeds to a next image formation cycle.

FIG. 3 shows a blower fan 42 serving as blowing means, which is the gistof the present invention.

The blower fan 42 is provided at an upper part on the back side insidethe apparatus body 1 so as to face an air inlet 41 provided on the backof the apparatus body 1. An air outlet 43 is formed at an upper part ofthe back of the sheet receiving unit 4 as shown in FIGS. 4 and 5. Theair outlet 43 and the blower fan 42 communicate with one another throughan air duct 44. The air outlet 43 is positioned in the vicinity ofoptical components such as the CCD 38.

Upon the image formation, the blower fan 42 is rotated and the outsideair is sucked through the air inlet 41. The sucked air is blown out fromthe air outlet 43 through the air duct 44 and supplied to the sheetreceiving unit 4 along the lower surface of the image scanner 3.

Incidentally, as the sheets ejected by the ejecting roller 18 are heatedby the fixing unit 15, the sheets emit heat after ejected. The imagescanner 3 is provided above the sheet receiving unit 4 and thetemperature of the image scanner 3 is made to rise by the heat emittedfrom the sheets collected in the sheet receiving unit 4. When thetemperature of the image scanner 3 is raised, the performances of thelens 37 and the CCD 38 serving as the optical components may bedeteriorated by the heat.

As described above, however, in the present invention, cool air isintroduced into the sheet receiving unit 4 along the lower surface ofthe image scanner 3 and, therefore, it is possible to insulate the heattransmitted to the lens 37 and the CCD 38 serving as the opticalcomponents and restrict the rise of the temperature of the image scanner3 or the lens 37, CCD 38 and the like provided in the image scanner 3.

Accordingly, it is possible to certainly prevent the deterioration ofthe image scanning performance caused by the rise of the temperature ofthe image scanner 3 or the lens 37, CCD 38 and the like provided in theimage scanner 3.

The outlet 43 of the cool air is positioned in the vicinity of theoptical components such as the CCD. Therefore, the cool air isconcentrated on the vicinity of the optical components and it ispossible to cool the optical components more effectively.

Moreover, as the cool air is not introduced directly into the imagescanner 3, dust or the like is not applied to the optical componentsinside the image scanner 3 or the like, image noise caused by the dustis hardly generated and the image scanning performance can be preferablymaintained.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An image forming apparatus comprising: a scanning unit which has aCCD therein and scans light on a document placed on a document tableportion to produce image information; an exposure unit which forms anelectrostatic latent image on an image carrier in accordance with theimage information produced by the scanning unit; an image formation unitwhich forms a developer image by supplying a developing agent to theelectrostatic latent image formed by the exposure unit; a transfer unitwhich transfers the developer image formed by the image formation unitonto an image-transferred member; an ejecting roller which ejects theimage-transferred member onto which the developer image is transferredby the transfer unit to outside, the ejecting roller being providedbelow the scanning unit and away from the CCD along a transferringdirection of the image-transferred member; a sheet receiving unitprovided below the scanning unit and receiving the image-transferredmember ejected from the ejecting roller; and an air opening provided inthe receiving unit, at least some part of the air opening being providedbetween the CCD and the ejecting roller.